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Any modern equivalent to the Sencore PA81 out there?

B

billh1963

Active Member
I would really like a bit of kit like the Sencore PA81. Used ones are hard to find and they are also getting old. Is there any modern equivalent being made?

I could build some dummy loads in a box and stick some ammeters/volt meters on it. But, would really like something nice with additional functions.
 
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Problem is with supply shortages many products are not available
There are also sound cards etc and software to run them for fft display and other functions
You just have to compare features and means to accomplish them
I have a amber 3500 but it is old and I would not recommend one unless you get it for a song and it functions correctly
The old hp 339a was okay, it had a few issues but there are fixes.
Many more, list your requiremts?
 
Basically I am looking for something to accomplish the following:

Test my receiver output on something before blowing up my speaker because the output is high voltage (did that with my Sansui G-7000). I learned a lesson on that one.
While testing, see what voltage is actually being delivered
And, while I'm in there (assuming all looks good) see if the receiver is delivering the power with the signal quality it should


I know I can do all this with my DMM, dummy loads, etc. But, having an "all in one' device that can do this (and more) while allowing me to connect a scope and other devices is appealing to me.
 
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I use both a Picoscope and Arta with an external sound card and a diy interface box. I think Room EQ Wizard (REW) is very capable as well. I don't think there is an affordable one box solution for everything.
John
 
nerdorama said:
I use both a Picoscope and Arta with an external sound card and a diy interface box. I think Room EQ Wizard (REW) is very capable as well. I don't think there is an affordable one box solution for everything.
John
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+1,000 You used the key word here... affordable.
 
FWIW, Sencore have always used very good quality parts, and very good design engineering in their US manufactured test equipment over the many, many decades they`ve been in business.

My (2) PA 81s (one for each bench are ~30 yrs. old and function properly within their specifications every time I power them up.

Unless the OP`s PA 81 has somehow (hard to do, due to thermal overload protection, and DC presence on the load disconnection protection) been abused !
I really can`t see any reason for concern(s) about the reliability and the unit failing factory spec/performance.

Replace all the handful of electrolytic capacitors, if concerned, for ongoing, and future confidence.

I have the greatest confidence in all my Sencore test equipment, or I wouldn`t have started purchasing any of their expensive brand new gear in the late eighties when my repair business started taking off, and have been time saving for all my audio repair needs.

However, I felt the need to do a easily done, & undone simple modification to both to better suit testing tube amplifiers by non invasively installing a mini switch to disconnect the unit`s DC presence protection circuit`s disconnect relay`s coil when testing tube amps so a very low frequency noise/pulse from the tube amp wouldn`t trigger the protection circuit thus removing the load resistor while the amp was being driven ! Not a good thing to do !
 
billh1963 said:
Yes, I do wish I had a PA81 :)
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My second PA 81 was purchased used from Audio Classics, after I stumbled across it on their site over 6 yrs ago while looking for something else.

It was offered at an very attractive price and in excellent physical/electronically shape, but minus it`s brick style power supply, which I readily substituted with a universal output voltage selectable SMPS laptop style for small money.
I powered it up for several full days and nights, to make sure there weren`t any internal circuit issues, before doing a complete check out of the factory specs, via the paper work (owner manual/service info), that came with my original PA 81 brand new purchase.
And when I was satisfied with the unit`s performance, I then modified it also for being selectable for tube or SS amp work, as described above like I did on my original PA 81.
Here they are at each at their respective benches.
DSCN0190.JPG DSCN0193.JPG
 
Quick question for PA81 owners. I picked up one a year ago and noted the fan doesn't come on. Is there a point, i.e x minutes at 100 watts or such that it comes on, or should it be on all the time? Thanks!
 
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Fishburritos said:
Quick question for PA81 owners. I picked up one a year ago and noted the fan doesn't come on. Is there a point, i.e x minutes at 100 watts or such that it comes on, or should it be on all the time? Thanks!
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As best that I can remember, Fishburritos, my PA-81`s fan briefly comes on when first powered up, like a kind of self test, and stays off until the internal temperatures rise high enough to trigger it to come on, and keeps running as long as I continue driving the amp, and a period of time afterwards, if its still powered on after I cease driving the amp.

Are you using the original OEM provided external ~12v power supply, or an aftermarket one ?

It`s been sometime since I`ve needed to use it for servicing/testing an amplifier.(all my many in use amplifiers keep operating without the need for checkout/service for many yrs., I`m lucky in that respect, I guess!)
 
Thank you Bill. I got my trusty flashlight and powered it on while watching the fan and it does in fact turn on for a very brief "self test" as you described. I really appreciated your feedback this was helpful. I guess 1 minute of 100 W / channel isn't enough to turn on the fan :)
 
Fishburritos said:
Thank you Bill. I got my trusty flashlight and powered it on while watching the fan and it does in fact turn on for a very brief "self test" as you described. I really appreciated your feedback this was helpful. I guess 1 minute of 100 W / channel isn't enough to turn on the fan :)
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You`re most welcome, Fishburritos, Sir.
The PA-81 is rated at 250 watts a channel, so the fan probably won`t kick in until you run the 100 watts for a sustained period of time, at least that`s my recollection of using mine, and the overall fans activation is also affected by the temperature of your environment that the dummy load is used in. (cooler room means the fan might take longer before it comes on, and sooner if the room`s temperature is higher)
If you really drive it hard near it`s max power rating, the PA-81 will ramp up the fan`s speed and then warn you with the thermal overheat indicator light, and to protect it`s self, will first kick the fan on max speed, and then will internally disconnect the load from the amp, via its internal protection relay, if you continue to drive it near its max rating !

I`m glad to hear that your PA-81`s turn on self test seems to be working properly.

Enjoy your use of it.
 
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